Conventional non-coherent radar systems transmit pulses of radio frequency energy and receive echoes of energy reflected from objects (such as targets of interest and clutter) located in the path of the transmitted energy. The azimuth resolution of such radar systems is limited by the azimuth beamwidth of the radar antenna radiating the transmitted energy pulses. For example, a radar system with a one degree azimuth beamwidth possesses an azimuth resolution of roughly one mile at a range of sixty miles from the radar site. The azimuth resolution is further affected by the distance between the detected objects and the radar site because the size of the range azimuth cell increases with range. Thus, at points distant from the radar site, the range azimuth cell encompasses more unwanted objects (clutter) in with the detected targets of interest. This results in a low signal-to-clutter ratio that adversely affects the ability of the radar system to resolve targets of interest for detection.
The traditional solution to the foregoing drawbacks of conventional non-coherent radar systems has been to utilize a coherent radar system. Such coherent systems typically include Doppler beam sharpening or synthetic aperture processing to improve signal-to-clutter ratios and azimuth resolution. However, coherent radar systems are more complex and significantly more costly than conventional non-coherent systems. Accordingly, there exists a need for a method and apparatus for improving the signal-to-clutter ratio and azimuth resolution of conventional non-coherent radar systems.